Suitability External Morphology and Some Biometric Characteristics of the Deep-water Redfish Actinopyga echinites (Echinodermata, Holothuroidea) in Cabgan Island, Barobo, Surigao del Sur, Philippines

Abstract

Actinopyga echinites (Jaeger, 1833) is among the most exploited holothurians for exports in the Philippines. Despite its economic significance, the lack of management initiatives resulted in declining wild stocks. This study provides information on external morphology and biometric characteristics like length-weight relationship and condition factor of A. echinites for proper management and sustainability. The study was conducted conducted in dry (March to May 2021) and wet (June to August 2021) seasons in Cabgan Island, Barobo, Surigao del Sur, where two stations with three plots (10 × 10m) were laid as monitoring stations. The results revealed that A. echinites showed coloration and shape variation to adapt to their environment. Higher mean length (7.7cm) and significantly higher mean weight (41.5g) were observed in A. echinites in Station 2 than the ones in Station 1 (p < 0.05). Both stations had a higher length (7.8cm and 8.4cm) and weight (38.4g and 49.7g) during wet than dry months, but only Station 2 showed significant differences for the two parameters. The population showed a negative allometric growth resulting in its leaner shape, with the slope of regression lines being 1.89 and 1.82 in Station 1 and 1.75 and 1.97 in Station 2 for the dry and wet months, respectively. Both stations recorded high condition factors but significantly higher during the wet season (p < 0.05). Further study on the reproductive biology and environmental characteristics is needed to enhance scientifically sound management interventions for the conservation and sustainability of A. echinites populations.